April 2009 Mineral of the Month

'BERYL'

The name beryl may possibly come from the greek word 'beryllos' which refers to a number of blue-green stones in antiquity. This precious gemstone mineral occurs as prismatic crystals which are sometimes terminated with small pyramids. The crystals are often striated parallel to their length and may be of massive size. Specimens up to eighteen feet long have been recorded. It also forms in massive, compact and columnar habits. The color varies greatly and gives rise to named varieties one might recognize such as Emerald, Morganite, Heliodor, Goshenite and Aquamarine. There is also a variety in red that was once referred to as Bixbite but has since been proved to be incorrect. This red variety is referred to as Red Beryl. Beryl is a member of the silicates group. Its chemical composition is Be3AI2SI6O18. It is quite durable coming in at 7-8 on the Mohs Scale. It is transparent to translucent with a vitreous luster. It has a white streak. Its specific gravity is 2.6 to 2.9. It has an indistinct cleavage with and uneven to conchoidal fracture.

Beryl of various colors is found most commonly in granitic pegmatites, but also occurs in mica schists in the Ural Mountains, and limestone in Colombia. Beryl is often associated with tin and tungsten ore bodies. Beryl is found in Europe in Norway, Austria, Germany, and Ireland, as well as Brazil, Colombia, Madagascar (especially morganite), Russia, South Africa, the United States, and Zambia. U.S. beryl locations are in California, Colorado, Idaho, New Hampshire, North Carolina, South Dakota, and Utah.

March 2009 Mineral of the Month

"RHODOCHROSITE"

The name Rhodochrosite comes from the Greek, rhodom, meaning rose and chrosis meaning a coloring refering to it's color. Rhodochrosite commonly occurs as a primary gangue mineral in moderate to low temperature hydrothermal veins also in high temperature metasomatic deposits and sedimentary manganese deposits or more rarely as a late stage hydrothermal mineral in pegmatites.

This mineral sometimes forms as rhombohedral, scalenohedral, prismatic or tabular crystals. More often, rhodochrosite occurs in massive, granular, stalactitic, glogular, nodular or botryoidal habits.

Its color is typically pink to red though it may also be brown, orange or yellowish. Manganese is what gives rhodochrosite its vivid pink to red color. The streak is white. It is transparent to translucent and has a vitreous to pearly luster.

It is a member of the carbonates family and its chemical composition is MoCO3. It is very soft coming in at 3-1/2 to 4 on the Moh's Scale. Its specific gravity is 3.7 and has an uneven fracture. Its cleavage is perfect rhombohedral.

Rhodochrosite is soluble in warm hydrochloric acid with effervescence.

Del Air Gemboree this Weekend! February 27-28, 2009

The Del Air Rockhounds Show is NEXT Weekend!!
See YOU There!!
CLICK HERE -To Listen to our Audio Ad!!



FREE ADMISSION AND FREE PARKING!
SHOP LATE! – FRIDAY, FEBRUARY 27^TH
WE’RE OPEN FROM 3PM TO 9:30 PM
SHOP EARLY! - SATURDAY FEBRUARY 28^TH

WE’RE OPEN FROM 10AM TO 5:00 PM

THE GEMBOREE IS AT 9650 RESEDA BLVD

AT THE CORNER OF SUPERIOR IN NORTHRIDGE

BEHIND THE UNITED METHODIST CHURCH!

We need ALL Members to help make it a successful show!!

February 2009 Mineral of the Month....'FELDSPAR'

'FELDSPAR GROUP'

UPPER LEFT: FELDSPAR; UPPER RIGHT: MICROCLINE var AMAZONITE; LOWER LEFT: LABRADORITE

Feldspar is a group of silicate minerals that is comprised of Albite, Andesine, Anorthite, Anorthoclase, Banalsite, Buddingtonite, Bytownite, Celsian, Dmisteinbergite, Hyalophane, Labradorite, Microcline, Oligoclase, Orthoclase, Paracelsian, Plagioclase, Reedmergnerite, Sanidine, Slawsonite, Stionalsite, and Svyatoslavite.

Feldspar is derived from the German words Feld meaning field and Spat meaning rock that does not contain ore. Feldspathic refers to materials that contain feldspar.

Feldspar is the name of a group of rock forming minerals which make up as much as 60% of the Earth's crust.

Feldspars crystallize from magma in both intrusive and extrusive igneous rocks. They can also occur as compact minerals, as veins and are also present in many types of metamorphic rock.
Feldspars are also found in many types of sedimentary rock.

Feldspar is a common raw material used in the production of ceramic and geopolymers. Feldspars are used for thermoluminescence dating and optical dating in earth sciences and archaeolgy. Feldspar is an ingredient in Bon Ami household cleaner. Feldspar is also used as an anti-caking agent in powdered forms of non-dairy creamers.

Feldspars are relatively hard at 6 on the Moh's Scale. Feldspars are generally light-colored including white, pink, tan, green or gray. The colors will vary due to impurities within the crystal structure. Feldspar is the mineral that gives Granite its pink, green or gray color,

Feldspar is mined from large granite bodies called plutons by geologists. They are also mined from pegmatites that were formed when the last fluid stages of a crystallizing granite became concentrated in small liquid and vapor-rich pockets. This allows the growth of extremely large crystals.

UPPER LEFT: ALBITE with QUARTZ; UPPER RIGHT: FELDSPAR; LOWER LEFT: ORTHOCLASE

Del-Air Education Team To Give Talk At Local Library

February 7th 2009 - 1:00 pm at the Woodland Hills Library
22200 Ventura Blvd. between Topanga Cyn Blvd. & Shoup

MAP

FREE!!!
Club members Keri Dearborn and Maxine Dearborn will be giving a talk on "Ice Age Animals". This should last for about an hour and is for adults and children. They will have a large collection of ice age bones, artifacts and pictures along with the Del-Air Education Team's specimens to enlighten, entertain and educate you on all the ice age animals. Take the time to stop by and see our exceptional education team in action.